Odd unselected/light-colored face when UV unwrapping torus?
That's the active, not unselected. Active is usually the last selected face/edge/vert. Sometimes it's very useful for example if you want to copy modifieres to the selected objects from the active or bake textures from other objects to the active, or merge verts to the last selected's position, or if you want to use UV wrapping by &quot;Follow Active Quads&quot;
https://docs.blender.org/manual/en/2.80/scene_layout/object/editing/transform/control/pivot_point/active_element.html